When I saw the mention here I figured this was going somewhere else. That IPFS document was unacceptable to have been passed and promoted as quality by Jack from Twitter without further review. I understand how it happened but it still pisses me off. We can't undo it and I'm not about to cry over it publicly or go back to them with corrections. Hive has everything going for it.
Regarding the witness question: We've always been on our own various servers. During the HF and immediately after we were cycling through our 5 different backup witnesses + main (although having them all crash in sequence in one day was not fun). Now we're down to fewer due to the need to upgrade the servers. But they are all decentralized, hosted in different areas of the world. The reason for that is lessons learned during the blackout in the early 2000s that took out the power grid in our area and kept it off for about a week. We also realized the difference in datacenter upkeep and tech physical response time between countries and services with the pandemic.
Having physical access to the main witness is not a good idea for most people. That would mean it's running out of their house or out of their office or a local datacenter. We tried it (local datacenter) and it was sub-optimal, mainly due to sharing the same infrastructure issues as the datacenter. Backup machines, however, can run out of a house or some local building very well.
The issue with some witnesses is that running a node is challenging, paying for it is challenging, and some like to start off with the 'in the box' step by step guide or to buy a ready-made one from Privex (who does a great job managing them). Where some witnesses upgrade once they learn more others just become complacent and shift their attention elsewhere. None of this is a simple matter to go through.
(Just to be clear here; a witness is not one server. It's one main server and at least one backup server or secondary server, usually more than one. It takes a long time to replay. You need to manage snapshots. There's a lot involved there.)